Swept-Source Optical Coherence Tomography Angiography Vascular Metrics as Biomarkers for Renal Function in Patients with Diabetes Mellitus.

PURPOSE: This study evaluates swept-source optical coherence tomography angiography (SS-OCTA) quantitative metrics as noninvasive biomarkers of diabetic nephropathy (DN) in patients with diabetes mellitus.

DESIGN

This is a cross-sectional study of patients with diabetes mellitus.

SUBJECTS: This study included 375 eyes of 234 patients imaged using 12 × 12-mm angiograms centered on the fovea.

METHODS

OCTA metrics that were analyzed included nonperfusion area (NPA), foveal avascular zone (FAZ) area, vessel density (VD), and vessel skeletonized density (VSD). These metrics were compared with the presence and severity of DN.

MAIN OUTCOME MEASURES: Primary outcomes were albuminuria (albumin-to-creatinine ratio ≥30 mg/g) and chronic kidney disease (CKD, estimated glomerular filtration rate [GFR] ≤60 or >60 mL/min/1.73 m2 with albuminuria). Secondary outcomes included albuminuria severity (A1: <30, A2: 30-300, A3: >300 mg/g), CKD severity (normal GFR: ≥90, mild CKD: 60-89, moderate-severe CKD: ≤59 mL/min/1.73 m2) and Kidney Disease: Improving Global Outcomes (KDIGO) risk categories for CKD progression and/or mortality. Subgroup analysis assessed early microvascular changes in patients with no or mild diabetic retinopathy (DR) and DN association. Multivariate regression adjusted for age, smoking status, glycated hemoglobin, and mean arterial blood pressure.

RESULTS

Of 234 patients, 145 (62%) had CKD and 111 (47%) had albuminuria. Increasing NPA was associated with albuminuria (odds ratio [OR]: 1.17, P = .038), CKD (OR: 1.06, P < .001), CKD severity (P < .05), and KDIGO risk categories on pairwise analysis (P < .05). VD and VSD were significantly different between extremes of KDIGO risk categories (very high vs low and moderate risk, P < .05) and albuminuria severity (A3 vs A1, P < .05). In the no/mild DR subgroup, more circular FAZ and higher VD were associated with absent albuminuria (P < .05).

CONCLUSIONS

NPA is a potential biomarker for predicting DN and is associated with DN severity. This study is the first to link OCTA metrics with KDIGO risk categories for CKD severity and mortality.